1. Field of the Invention
This invention relates to a process for making 2-oxindole-1-carboxamides which comprises reacting a 2-oxindole with trichloroacetyl isocyanate to produce a novel N-trichloroacetyl 2-oxindole-1-carboxamide which is then hydrolyzed to a 2-oxindole-1-carboxamide. The latter compounds are valuable analgesic and anti-inflammatory agents and/or useful as intermediates for such agents.
2. Description of Related Art
Graf, Angew. Chem. Internat. Edit. 7, 172-182 (1968) describes addition of amines and carboxamides to chlorosulfonyl isocyanate to produce N-chlorosulfonylureas and acyl N-chlorosulfonylureas, respectively.
U.S. Pat. Nos. 4,652,658 and 4,665,194, issued Mar. 24, 1987 and May 12, 1987, respectively describe a process for making 2-oxindole-1-carboxamides by reacting a 2-oxindole with chlorosulfonyl isocyanate to produce a N-chlorosulfonyl-2-oxindole-1-carboxamide which is then hydrolyzed to a 2-oxindole-1-carboxamide.
U.S. Pat. Nos. 3,634,453, 4,556,672 and 4,569,942, issued Jan. 11, 1972, Dec. 3, 1985 and Feb. 11, 1986, respectively, describe preparation of 2-oxindoles of formula (I) below.